For a given input value $x$, the function $f$ outputs a value $y$ to satisfy the following equation. $-5x-4y=-8$ Write a formula for $f(x)$ in terms of $x$. $f(x)=$
Explanation: $f(x)$ expresses $y$ as a function of $x$. To arrive at a correct formula, all we have to do is solve the equation for $y$. $ \begin{aligned}-5x-4y&=-8\\\\ -4y&=5x-8\\\\ y&=\dfrac{5x}{-4}-\dfrac{8}{-4}\\\\\\ y&=-\dfrac{5}{4}x+2\end{aligned}$ Therefore, this formula expresses $y$ as a function of $x$ : $ f(x)=-\dfrac{5}{4}x+2$